1. Computer
An electronic device, operating under the
control of instructions stored in its own
memory unit, that can accept data
(input), manipulate the data according to
specified rules (process), produce information
(output) from the processing, and store the
results for future use.

2. Information Processing Cycle
STORAGE
INPUT PROCESS OUTPUT

3. INPUT
• The collection of raw data from the outside world so it
can be put into an information system. Putting the
acquired data into the information system.
Examples:
• The payroll clerk collects workers' timecards so she knows how many hours
each person worked that week and types the hours from the timecards into a
spreadsheet
• Collecting jokes for a joke book and typing jokes into a word processor.
• Using a form on a website to collect visitors' opinions
Typical input devices:
• Keyboards, mice, flatbed scanners, bar code readers, digital data tablets
(for graphic drawing), electronic cash registers

4. PROCESSING
A process is a program that is running on your computer. This can be
anything from a small background task, such as a spell-checker or system
events handler to a full-blown application like Internet Explorer or
Microsoft Word. All processes are composed of one or more threads.
The most important part of these components is the central processing
unit (CPU) also called the processor. The CPU is the brain of your
computer it is the key component in interpreting computer program
instructions and processes data.
The next most critical element of a processing is RAM, often referred to as
"primary storage" or "main memory". Random Access Memory (RAM)
temporarily stores information that the CPU uses while the computer is on
and is erased when the computer is turned off.

5. Output
• In information processing, output is the process of
transmitting the processing information
• Essentially, output is the presentation of any data exiting a
computer system. This could be in the form of printed
paper, audio, video. In the medical industry this might include
CT scans or x-rays. Typically in computing, data is entered
through various forms (input) into a computer, the data is
often manipulated, and then information is presented to a
human (output).

6. Typical output devices:
• Monitors
– Pixels: Images are created with dots of lights called picture
elements, or pixels. More pixels = higher resolution. Resolution
is the maximum number of pixels the monitor can display
– Basic VGA is a pixel grid 640 X 480
– Super VGA is 1,024 X 768
– A video card, (also referred to as a graphics accelerator card,
display adapter, graphics card, and numerous other terms), is an
item of personal computer hardware whose function is to
generate and output images to a display .
• Printers
– Laser - laser beams bond toner to paper
– Ink jet - fine stream of ink
– Dot Matrix - pins & ribbon

7. Storage
• Computers usually have one or more disk
drives, commonly referred to as a hard drive—
devices that store information. The disk preserves
the information even when your computer is
turned off. All computers have a hard disk
drive that can hold massive amounts of
information; they usually serve as your
computer's primary means of storage, holding
almost all of your programs and files. The hard
disk drive is normally located inside the system
unit.

8. Examples of mass storage devices
• Disk storage – hundreds of thousands of cycles latency, but very large
– Hard disks : Very fast and with more capacity than floppy disks, but also more
expensive. Some hard disk systems are portable (removable cartridges ), but most are
not.
– Solid State Drives have no moving parts and utilize non-volatile memory chips.
– Floppy Disks: (almost obsolete!)
• Tertiary storage –
– Optical storage: Unlike floppy and hard disks, which use electromagnetism to encode
data, optical disk systems use a laser to read and write data. Optical disks have very
large storage capacity, but they are not as fast as hard disks. Examples: CD, CD-R, CD-
RW, DVD or DVD-R
– Tapes: Relatively inexpensive and can have very large storage capacities, but they do
not permit random access of data.
• Flash Memory – faster than disk storage, with up to 4GB or more of
data, transferring (usually) over universal serial bus (USB)

9. Types of Computers
• Computers come in all sorts of shapes and sizes and serve a variety of
purposes. Not too many years ago, computers were the size of a large
room and consumed huge amounts of power. However, with the advances
in technology, computers have shrunk to the size of a watch. Depending
on the processing powers and sizes of computers, they have been
classified under various types. Let us look at the classification of
computers.
Different types of Computers :
•Supercomputers: Highly calculation-intensive
tasks can be effectively performed by means of
supercomputers. Quantum
physics, mechanics, weather forecasting, molecular
theory are best studied by means of
supercomputers.

10. •Mainframe Computers: Large
organizations use mainframes for highly
critical applications. Most of the
mainframe computers have the capacity
to host multiple operating systems and
operate as a number of virtual machines
and can thus substitute for several small
servers.
•Microcomputers: A computer with a
microprocessor and its central processing unit is
known as a microcomputer. When supplemented
with a keyboard and a mouse, microcomputers can
be called as personal computers. A monitor, a
keyboard and other similar input output
devices, computer memory in the form of RAM
and a power supply unit come packaged in a
microcomputer. These computers can fit on desks
or tables and serve as the best choices for single-
user tasks.

11. Personal computers come in a variety of forms such as desktops, laptops and
personal digital assistants. Let us look at each of these types of computers.
•Desktops: A desktop is intended to be
used in a single location and are widely
popular for daily use in workplace and
home.
•Laptops: Similar in operation to desktops, laptop
computers are miniaturized and optimized for
mobile use. Laptops run on a single battery or an
external adapter that charges the computer
batteries. They are enabled with an inbuilt
keyboard, touch pad acting as a mouse and a liquid
crystal display.

12. •Personal Digital Assistants (PDAs): It is a handheld
computer and popularly known as a palmtop. It has a touch
screen and a memory card for storage of data. PDAs can also
be effectively used as portable audio players, web browsers
and smart phones. Most of them can access the Internet by
means of Bluetooth or Wi-Fi communication.

13. •END